Pillowcases that fit after washing

A pillow has thickness as well as length

A pillowcase can match the length printed on a pillow packet and still feel tight. A plump filling uses some of the available cloth as the case curves around it. Measure your existing pillow from seam to seam without flattening it aggressively, and compare the result with the case manufacturer's intended pillow size.

An old case that fits well offers another reference, but measure it after laundering, laid flat. Note whether its envelope flap stays tucked in or whether the pillow regularly escapes. The opening matters as much as the outside rectangle. A narrow zip opening can make fitting a full pillow awkward even when the finished dimensions are adequate.

Read the dimensions carefully

Some shops give finished case dimensions; others state the pillow size the case is designed for. Ask which is meant if the listing is unclear. Names such as standard and king vary between product ranges. The words are convenient for browsing, not a substitute for centimetres.

Allow for any shrinkage information the manufacturer supplies. Do not add an arbitrary percentage to every cotton case. Fabric construction and finishing differ, and a product may already include an allowance. If you need several cases for matching pillows, try one through its permitted wash cycle before committing to the full quantity, where the seller's purchase and return conditions allow this.

A very loose case is not automatically the safer choice. Excess fabric can bunch beneath the head, and a long unused end may twist around the pillow. The aim is a case that accepts the pillow without strain and closes naturally. Check that decorative piping, embroidery or a zip pull sits where it will not bother the person using it.

Make changes in pairs

When replacing a pillow, check its case at the same time. A new, fuller pillow may expose a fit problem that the older compressed one did not. Keep the previous case for a different suitable pillow rather than forcing it over the new filling.

During washing, close zips if the care instructions require it and avoid catching the case on other fastenings. After drying, reshape it gently along its seams. If one side has become noticeably shorter or the closure is distorted, compare it with your recorded measurements before ordering more from the same range. Repeated tugging is a sign to revisit the fit, not a normal part of making the bed.

When the pillow has an unusual shape

A contoured pillow or one with a substantial gusset may need a case designed for that construction. Measure its maximum dimensions but also check the intended pairing in the pillow instructions. Pulling an ordinary flat case tightly across a shaped pillow can change the way the surface sits.

If a protective cover is used beneath the pillowcase, include it when trying the fit. Its seams and thickness take room, especially around a full pillow. Check that both layers can be removed without stressing their fastenings. A case that fits the bare filling may be the wrong size for the complete arrangement used on the bed.